PROJECT SUMMARY Alcohol use puts adolescents with suicide-related thoughts and behaviors at high risk for attempted suicide and suicide death. Typically, adolescents who make a suicide plan or attempt are admitted to an inpatient psychiatric hospital for a brief time period in order to be evaluated. These inpatient units rarely address alcohol use in a comprehensive fashion as the adolescent's suicide risk is the primary focus of treatment. Given the significant role alcohol can play in subsequent suicidal ideation and attempts, greater attention to the assessment and initial treatment of alcohol use in adolescent inpatient psychiatric settings is essential, with a post-discharge follow-up plan playing a critical role in the safety of the suicidal adolescent. The proposed study will develop and test iASIST (integrated Alcohol and Suicide Intervention for Suicidal Teens), a novel adjunctive intervention for alcohol use and alcohol-related suicidal thoughts and behaviors. iASIST involves three components: 1) one 60-90 minute individual intervention with the adolescent in which motivational enhancement techniques are used to explore alcohol use as a risk factor for continued suicide-related thoughts and behaviors, build the adolescent's motivation to reduce or stop their alcohol use, and create a change plan if the adolescent is ready, 2) a subsequent 30 minute family intervention in which the interventionist facilitates a discussion between the adolescent and the parent about the change plan using motivational enhancement techniques to align the parent with the adolescent to strengthen the adolescent's self-efficacy and commitment to the change plan as well as the parent's confidence and ability related to supporting the adolescent in the change plan, and 3) a post-discharge mHealth booster to adolescents focused on strengthening their commitment to the change plan, and to parents focused on their commitment, confidence, and ability related to supporting the adolescent in the change plan. First, we will refine the design of the mHealth booster by obtaining feedback on proposed content, interface, and functionality via in-depth interviews with 8 adolescents and 8 parents who completed the intervention arm of PI O'Brien's current pilot trial of the in-person component of iASIST. Second, we will conduct an open trial of iASIST with 10 adolescents and their parents to test the full adaptation of iASIST (i.e., in-person sessions and mHealth booster) and make subsequent changes for the final study phase. Third, we will conduct a randomized trial with 50 adolescents and their parents to test the feasibility and acceptability of iASIST as well as alcohol- and suicide-related outcomes at 3 months post-discharge. Intervention participants will be compared to adolescents and their parents who will receive an attention-matched comparison condition focused on the role of a healthy lifestyle in mental health that includes a post-discharge mHealth control targeting the maintenance of a healthy lifestyle. The data from this project will inform the preparation of a fully powered, future trial of the intervention.